I cannot get the game to let me change an 'O' back to either a blank or an 'X'. I don't see anything in the Rules or Help that covers this. Is this an actual glitch, or is there something I'm missing in the Rules?

I also don't understand what that pushpin thing is for, nor how to control it.

I like the idea of this puzzle, but I think more explanations would be nice. Don't bury information deep; put it out in front where we can find it quickly.

There is an 8x8 grid next to text that gives a very basic explanation of things. I had a lot of trouble making things work, and eventually gave up. When I tried the first (Free) game on the actual page of puzzles for the week, I was able to rotate easily from blank to 'X' to 'O' to blank. No idea what the issue was on the other page.